Oscillating foil propulsion system and method for controlling a motion of an oscillating movable foil

Abstract

The invention relates to an oscillating foil propulsion system comprising a movable foil, a pitch mechanism connected to the movable foil and configured to control a pitch motion of the foil, a heave mechanism connected to the movable foil and configured to control a heave motion of the foil, and wherein at least one of the pitch and heave mechanisms is configured to adjust an amplitude of the respective motion of the movable foil. The invention further relates to a method for controlling a motion of an oscillating movable foil of a marine propulsion system.

1 . An oscillating foil propulsion system comprising:
 a movable foil,   a pitch mechanism connected to the movable foil and configured to control a pitch motion of the foil, and   a heave mechanism connected to the movable foil and configured to control a heave motion of the foil, wherein at least one of the pitch and heave mechanisms is configured to adjust an amplitude of the respective motion of the movable foil.   
     
     
         2 . The oscillating foil propulsion system according to  claim 1 , wherein the pitch mechanism is configured to adjust a pitch angle of the pitch motion of the foil. 
     
     
         3 . The oscillating foil propulsion system according to  claim 1 , wherein the pitch mechanism is configured to cause the amplitude of the pitch motion to change from a first peak amplitude to a substantially different peak amplitude. 
     
     
         4 . The oscillating foil propulsion system according to  claim 3 , wherein the substantially different peak amplitude is greater than or less than the first peak amplitude by 5-70 degrees. 
     
     
         5 . The oscillating foil propulsion system according to  claim 1 , wherein the pitch mechanism is further configured to adjust a frequency of the pitch motion of the foil. 
     
     
         6 . The oscillating foil propulsion system according to  claim 1 , wherein the heave mechanism is configured to adjust a heave of the heave motion of the foil. 
     
     
         7 . The oscillating foil propulsion system according to  claim 6 , wherein the heave mechanism is configured to cause the amplitude of the heave motion to change from a first peak amplitude to a substantially different peak amplitude. 
     
     
         8 . The oscillating foil propulsion system according to any of  claim 1 , wherein the heave mechanism is further configured to adjust a frequency of the heave motion. 
     
     
         9 . The oscillating foil propulsion system according to  claim 1 , wherein at least one of the pitch mechanism and the heave mechanism includes a crank mechanism. 
     
     
         10 . The oscillating foil propulsion system according to  claim 9 , wherein the crank mechanism includes a crank arm, which is rotatable around an axis of rotation, and wherein the length of the crank arm is adjustable or the crank arm includes a coupling which is movable along the crank arm. 
     
     
         11 . The oscillating foil propulsion system according to  claim 1 , wherein at least one of the pitch mechanism and the heave mechanism includes hydraulic cylinders and/or the heave mechanism includes a rack and a movable base module. 
     
     
         12 . The oscillating foil propulsion system according to  claim 1 , wherein at least a portion of the pitch mechanism and at least a portion of the heave mechanism are configured to be housed within a hull of a vessel and wherein the movable foil is configured to be outside of the hull of the vessel. 
     
     
         13 . The oscillating foil propulsion system according to  claim 1 , wherein the oscillating foil propulsion system is partially housed within a azimuthing housing, and wherein a connector extends from outside the azimuthing housing to inside the housing and wherein the movable foil is configured to be outside of the azimuthing housing. 
     
     
         14 . The oscillating foil propulsion system according to  claim 1 , further comprising a computer readable medium having stored thereon a set of computer implementable instructions capable of causing a processor, in connection with the pitch mechanism, to control a pitch angle of the movable foil, a frequency of the pitch motion, and an amplitude of the pitch motion. 
     
     
         15 . The oscillating foil propulsion system according to  claim 1 , further comprising a computer readable medium having stored thereon a set of computer implementable instructions capable of causing a processor, in connection with the heave mechanism, to control a heave of the movable foil, a frequency of the heave motion, and an amplitude of the heave motion. 
     
     
         16 . A method for controlling a motion of an oscillating movable foil of a marine propulsion system, comprising the steps of:
 varying an amplitude of a pitch motion of the movable foil to change from a first peak amplitude to a substantially different peak amplitude, and/or   varying an amplitude of a heave motion of the movable foil to change from a first peak amplitude to a substantially different peak amplitude.   
     
     
         17 . The method according to  claim 16 , further comprising:
 receiving at least one input, said input selected from the group of: a speed of a vessel, a direction of a local fluid flow in relation to the movable foil, a velocity of a local fluid flow in relation to the movable foil, and a desired thrust of the vessel, and   wherein at least one of the amplitude of the pitch motion and the amplitude of the heave motion is varied based on said at least one input.   
     
     
         18 . A non-transitory computer readable medium having stored thereon a set of computer implementable instructions capable of causing a computing device, in connection with a pitch mechanism capable of controlling a pitch motion of a movable foil and a heave mechanism capable of controlling a heave motion of the movable foil, to vary an amplitude of at least one of the pitch motion and the heave motion of the foil of an oscillating foil propulsion system. 
     
     
         19 . The non-transitory computer readable medium according to  claim 18  capable of causing the computing device to vary at least one of a pitch angle, a heave, a frequency of the pitch motion, a frequency of the heave motion, the amplitude of the pitch motion, and the amplitude of the heave motion depending on at least one of:
 a speed of a vessel, 
 a direction of a local fluid flow in relation to the movable foil, 
 a velocity of the local fluid flow in relation to the movable foil, and 
 a desired thrust of the vessel. 
 
     
     
         20 . (canceled)